1. Field of the Invention
The present invention relates to an apparatus for reducing flickers of an encoder, and particularly to an improved apparatus for reducing flickers of an encoder capable of advantageously reducing flickers occurred when video signals are convened digitally from a non-interlace scanning method to an interlace scanning method.
2. Description of the Conventional Art
Conventionally, the flickers occur in the video signals outputted from an encoder when the video signals convened from the non-interlace scanning method to the interlace scanning method are encoded at an RGB encoder. Thus, since the video signals are usually scanned 60 times per second in the non-interlace scanning method and divided into the even field and the odd field in the interlace scanning method by being scanned 30 times per second, the flickers are shown therein as an elastic line swinging up and down, which increase when the brightness differences adjacent colors at the flame of the non-interlace scanning before encoding is increased.
In an attempt to reduce such flickers, an analog method of reducing the brightness difference in adjacent colors is used. The conventional apparatus for reducing flickers using such a method, referring to FIG. 1 includes a graphic controller 1 for outputting a pixel signal of a scanning line unit when the video signal of the non-interlace scanning method is inputted thereto, a line store 2 for storing a pixel signal of nth odd scanning signal among pixel signals of a scanning line unit outputted from the graphic controller 1, a line store 3 for storing a pixel signal of nth even scanning line among pixel signals of a scanning line unit outputted from the graphic controller 1, digital/analog converters(DAC) 4 and 5 for converting the pixel signals of the nth odd and even scanning lines outputted from the line stores 2 and 3, an analog adder 6 for adding the pixel signal of the adjacent scanning line from the digital/analog converters 4 and 5, a divider 7 for computing an average value by dividing the output signal of the analog adder 6 by two, and an encoder 8 for finally outputting the video signal of NTSC or PAL method of the interlace scanning method by encoding the output signal of the divider 7.
The operation of the conventional apparatus for reducing the flickers of an encoder will now be explained.
To begin with, the graphic controller 1 outputs the pixel signal of the scanning line unit from the video signals of the interlace scanning method inputted thereto. Thereafter, the line stores 2 and 3 each store the pixel signals corresponding to the nth odd and even scanning lines among pixel signals of the scanning line unit outputted from the graphic controller 1. The digital/analog converters 4 and 5 convert the pixel signals of the nth odd and even scanning lines outputted from the line stores 2 and 3 to the digital/analog signals and output the converted signals to the analog adder 6. The analog adder 6 adds the pixel signal of the adjacent scanning line outputted from the digital/analog converters and outputs the added signals to the divider 7. The divider 7 computes the average value by dividing the signals added by the pixel signal of the adjacent scanning line by two at the analog adder 6 and outputs these signals that have converted from the video signal of the non-interlace scanning method to the video signals of the interlace scanning method, now taking the form of the obtained average value. Thereafter, the analog encoder 8 encodes the signals outputted from the divider 7 and outputs the video signals of the NTSC or PAL of the interlace scanning method by encoding the signals outputted from the divider.
However, the conventional apparatus for reducing flickers of an encoder has problems in enhancing the resolution quality thereof because the video signals are processed in a state of analog, in addition to that, the external noise may be mixed thereinto.